The primary functions of the NCCTG Pathology Committee are to: 1. Assure accurate histopathologic diagnosis for patients participating in NCCTG clinical trial through its quality assurance program. 2. Facilitate translational research by procuring, processing, and providing tissue specimens to the Research Base Tissue Resource for laboratory correlative science studies. 3. Participate in development and review of NCCTG clinical trials. 4. Conduct research on the prognostic significance of various parameters and collaborate on translational research studies with laboratory scientists at the Research Base. Over the past grant period, the Pathology Committee has reviewed tissue specimens from 2,887 patients on 26 protocols to assure correct diagnosis. In addition, 34 discrepancies in diagnosis were resolved at the semi-annual Group meetings, and 24 colorectal cancer and eight breast cancer cases were audited to assure correct diagnosis in these tumor types where mandatory review was not instituted. Members of the Pathology Committee have provided 7,175 tissue blocks to the Research Base Tissue Resource from patients participating in 47 NCCTG clinical trials in support of laboratory correlative studies of prognostic and predictive markers since 1994. Eight manuscripts have been published since 1996, reporting laboratory correlative studies in breast cancer, colorectal cancer, lung cancer, ovarian cancer, and brain tumors using NCCTG tissue blocks. Several other studies are in progress. Other, NCCTG pathologists were authors of co-authors of 14 published and three submitted manuscripts during the past grant period. Future plans are to continue our quality assurance program, with mandatory pathology reviews where it is warranted and selective audits where appropriate. We will maintain our excellent record of tissue block submission for laboratory correlative studies, and will develop systems to procure fresh tumor tissue for molecular studies where required. Finally, we will investigate pathologic prognostic factors of interest to the NCCTG community physicians and clinical investigators, and collaborate on molecular studies with members of the Translational Research Coordinating Committee.